What do fruit bats have to do with dinner? A new study finds that in Ghana, a key component of the wild meat market has long gone overlooked. Fruit bats are playing an increasingly large role in the trade, and overhunting of the flying mammals may endanger humans along with the bats.

For many people, “bushmeat,” or wild animal meat, is an important source of income or protein. Overhunting, however, often means that fewer animals are left to provide vital ecosystem services, such as pollinating plants or keeping pest species in check. But bushmeat is not always sold in easily-observed markets, making it harder for conservationists to create an accurate picture of which species are at risk.

The African Straw-colored Fruit Bat (Eidolon helvum) may not seem like a likely candidate for bushmeat. With a wingspan of nearly two feet, it is one of the larger bat species, but it carries nowhere near as much meat as antelopes, pigs, and other popular bushmeat species. But the bats do congregate in large colonies, making them a tempting target, a team led by A.O. Kamins of the Cambridge Infectious Disease Consortium and Institute of Zoology in London reports in Biological Conservation.

To get a clearer picture of how bat bushmeat “gets from the site of capture to the consumer’s table,” Kamins collaborated with researchers from Ghana and the United Kingdom. The researchers interviewed 551 Ghanaians, including bat hunters, consumers, and vendors, in cities and towns across southern Ghana, including the capital of Accra. Researchers began by approaching hunters they saw shooting the bats, or vendors they saw selling them in the marketplace, who then directed them to additional hunters and vendors. Although Straw-colored bats are listed as a near-threatened species, it is legal to hunt them in Ghana, so it was not difficult to get vendors and hunters to answer questions. The researchers found that there were two kinds of hunters: subsistence hunters, who hunted the bats to feed themselves and their families, and commercial hunters, who sold their catch to vendors. A few consumers owned chopbars (local restaurants); the rest were individual consumers.

Overall, hunters sold 128,000 bats yearly, the researchers estimated. If accurate, the estimate suggests that conservationists have undervalued the bat bushmeat trade; many surveys do not even mention E. helvum. One reason for this underestimate, the authors write, is that sales are not always visible; clients often seek hunters out personally, rather than encountering them in the general marketplace. Another reason is that these bats sell very quickly. Many vendors reported that they sold out almost immediately, and the trade is limited only by how many bats they can get.

Unfortunately for Straw-colored bats, it appears that the trade in bat bushmeat is on the rise. Larger species are becoming overhunted and harder to find, and Kamin notes that “the peak season reported for hunting bats corresponds with the main dry season in Ghana.” That means the bats provide an important food source during this “lean agricultural season.” Consumer also said they prefer to eat fruit bats because insect-eating bats have an unappetizing taste and smell. Straw-colored bats are particularly vulnerable to hunting, the authors note. They breed slowly, and gather in large roosts that are easily found and hunted. There are five known major colonies of E. helvum in Ghana, the researchers report, with an estimated population of 2.5 million. But they calculate that a population of 10 million bats would be necessary to support the current rate of hunting.

Another reason this commodity chain needs to be better understood, the authors write, is that Straw-colored bats are an ideal host for a variety of diseases, such as Ebola virus, that can be transmitted to humans. Understanding the mechanics of the trade is “the first step towards identification of potential risk groups” – and developing “effective management policies to both benefit E. helvum conservation and to contribute to the economic and food security of the growing Ghanaian population.” — Katharine Baggaley | November 21, 2011